. >>> president obama will travel to boston on thursday. now we go to chris cuomo live for us in boston. it seems here we are 24 hours more or later and nobody seems to have a real clue who has done this or why. >> reporter: that shouldn't be surprising, piers, these investigations take a very long time to develop, especially starting with being multifactorial, no group claiming responsibility. so much ground to canvas, this is going to be a difficult investigation. i think it's good news that the authorities said in their presser that they're in no rush. very often as we both know, haste makes waste when it comes to an investigation. this is about getting it right. >> that is true. i imagine there'll be some people in boston who will be concerned for their safety. that the perpetrator of this atrocity is still at large. >> that's absolutely true. at least that's what they believe at this time, piers. but what is also true, there's never been as large a military and police presence in this city as there is right now. in the presser, they as